For example, as reactors applied for a vehicular booster circuit, a reactor which have a resin mold component covering the circumference of an annular magnetic core, and which have a coil around the outer circumference of the resin mold component is known.
Conventionally, according to this type of reactors, as described in JP 2013-026420 A, JP 5274208 B. and JP 5465151 B, the; entire reactor is housed in a metal casing formed of aluminum, etc., and a filler is injected and solidified between the reactor and the casing. When fastening the reactor employing such a structure to an attaching position such as a vehicle body, the casing is fastened to the attaching site by means of, for example, screws.
However, according to the above conventional technologies, a resin is applied and solidified around the circumference of a core set in a mold to integrate the core and the resin molding with each other, and then the integrated core and resin molding are set in the casing. Hence, at the time of assembling of the reactor, a work to fasten both the core and the resin molding set in the casing so as not to move within the casing is necessary, and there is a disadvantage such that the number of manufacturing steps of the reactor increases.
The conventional casing is a box shape having an opened upper surface, and therefore leakage magnetic fluxes generated by the coil housed in the casing traverse the bottom of the casing. Aluminum that has excellent heat dissipation is often used for the metal casing. However, according to the conventional casings, since the side surface of the casing is placed so as to face the yoke portion of the core, the inductance decreases due to the shielding effect against the magnetic fluxes leaking from the back surface of the core.